This invention relates generally to a liquid dispenser, and more particularly to a device for discharging a chemical concentrate from the interior of a container into the flush tank of a toilet only at the end of the tank flush cycle.
Prior art chemical dispensers for flush tanks are known for dispensing a cleaning fluid into the flush tank of a toilet by employing a positive pumping or piston action. Such dispensers have different modes of operation and often require the chemical container to be inverted in the tank so that the container neck, or a member affixed thereto, functions as a stationary piston coacting with a dispensing member or float. Dispensing may occur near the end of the flush cycle, or may be responsive to rising water levels in the tank. Some of the inverted container-type dispensers employ no positive pumping action, and most of such devices are relatively complex in their arrangement and operation and are somewhat deficient in that they inaccurately meter the chemical into the flush tank.
A flush tank dispenser having its container positioned upright in the tank and employing a positive pumping action for dispensing the product is disclosed in U.S. Pat. No. 3,341,074 to Pannutti. However, the length of the stroke required during the displacement action allows for undue migration of the chemical into the flush tank thereby resulting in an overtreating of the tank water and a needless waste of the chemical. Besides, more tank water than necessary is permitted to enter the container during the tank refill mode before the chemical is sealed off from the exterior of the container. And, tank liquid during the tank refill mode must enter the container which is open in the same direction as the rising water level so that measures must be taken to ensure an adequate refilling of the container with tank liquid before it is sealed off.